55 



Grevillea robusta, a. Cunn. 



" Silky Oak." Found in New South Wales and Queensland. 



" In the India Museum is a sample of gum rather like that of 

 Moringa, of a vinous-red colour, and but little soluble. It is said 

 to have been obtained from this tree, which is cultivated to a 

 limited extent in Mysore. It has a bright shining resinoid frac- 

 ture, which it retains. It is much mixed with pieces of friable 

 bark, to which it adheres. The gum is only botanically interest- 

 ing" (Cooke, "Gums and Resins of India"). 



In some notes on the Shevaroy Hills for 1881, by Deputy- 

 Surgeon-General Shortt, the following passage occurs : — " Of the 

 plants introduced in these liills, I have to notice a peculiarity as 

 regards Grevillea rohusta. One tree, which is now eleven years 

 old, has for the last two years during the rains produced spon- 

 taneously each year about ten ounces of a translucent gum, which 

 has no smell or particular taste, is of a pale yellow colour, and 

 mixes readily with water, when it forms a whitish-brown coloured 

 mucilage, and as a paste answers all the purposes of the so-called 

 gum arable for adhesive purposes. The other Grevillea trees are 

 some two or three years younger, and have not as yet evinced any 

 disposition to produce gum." This finding of a gum so adhesive 

 in the Proteaceje is not borne out by the author's experiments. 



Fleury experimented upon gum of this species from Algeria 

 (Journ. Plictrm. [5], ix., 479-480 ; Jonrn. Chem. Soc, xlviii., 238). 

 He speaks of it occurring "frequently," and being similar in 

 appearance to cherry gum. It is yellowish-red, slightly trans- 

 lucent, and slightly friable. In water it swells a little, and 

 slowly produces a very persistent white emulsion, which passes 

 through all filters. It contains no starch, but gives 3 per cent, 

 of ash, principally calcium carbonate and a little potash. Tlie 

 emulsion, treated with absolute alcohol, gives a copious precipi- 

 tate of gum proper. When the alcoholic solution is evaporated 

 it gives 5-6 per cent, of a reddish transparent resin, with slightly 

 acid properties ; this is soluble in alkalies and carbon bisulphide. 



Common as tliis species is in this its native country of Aus- 

 tralia, it has not yet been my good fortune to find any gum on it 

 M. Fleury's specimen is almost a gum-resin ; exudations from a 

 Hakea and a Xylomelum examined by me yield true gums, witli 

 not a trace of resin. But Grevillea striata yields an exudation 

 which is mainly resin, so we must come to the conclusion that 

 the Proteacea? yield both gums and resins. 



Grevillea striata, R. Br., B. FL, v. 462. 



" Beef-wood." Found in South Australia, New South Wales, 

 <^ueenslandj and Northern Australia. 



